In 1982 the Canadian Astronomer, Paul Hickson,
using the red prints from the Palomar Observatory Sky Survey,
published a catalog of 462 galaxies thought to exist within compact
groupings. These groupings are now referred to as "Hickson
Compact Groups" (HCG). Compact groups are typically four
or five galaxies in close physical proximity to one another. They
are among the densest concentrations of galaxies known, comparable
to the centers of rich galaxy clusters. Compact groups are worthy
of intense study as they provide a rich opportunity to study galaxy
interactions and merger events. Proof of proximity is difficult
and relies on a variety of observational evidence including common
redshifts, space distribution, photometry, and other parameters
together known as Hickson's isolation criteria.

The true nature of compact groups has been
the subject of much controversy. Interpretations have run the
gamut from the belief that all represent true physical associations
to the belief that they are mere chance alignments. More than
likely most are true physically related dynamically bound systems
although some are certainly projection artifacts. A recent analysis
has shown beyond question that almost half of all HCG galaxies
show features indicative of interactions or mergers. This figure
is bound to rise with more detailed studies.

Current theory is that compact groups represent
physically related galaxies that are in the process of merging
into a single object, most likely an elliptical galaxy. Compact
groups are relatively short lived entities that form via mergers
of galaxies within loose subsystems and groupings. Simulations
predict that merging of the group members should proceed rapidly
within one billion years to form an elliptical galaxy. Hickson
groups are therefore snapshots at various stages in this merging
process. The more evolved groups are smaller and more deficient
in neutral hydrogen while the least evolved resemble galaxies
in looser groups. Observational evidence shows that interaction
is occurring in a large fraction of galaxies in HCG supporting
this model for the origin and evolution of HCG. The cosmological
implications of compact groups are significant. Astronomers believe
they may represent an intermediate stage between loose groups
and individual galaxies. A better understanding of the nature
of HCG could help explain galaxy formation on a larger scale in
the early universe.

The four dominant members of Hickson Compact
Group 44 consists of three spirals and an elliptical galaxy, NGC
3190, 3193, 3185, 3187. Two dwarf galaxies are also part of the
group but are not included in the Hickson catalog. Signs of tidal
encounters between members of HCG 44 are present. NGC 3190, the
dominant edge-on spiral shows considerable warping of its dustlane
on the side nearer to NGC 3187. NGC 3187, also known as ARP 316a
shows numerous tidal tails well above and below its disk plane.